This command is used by guest to gettimeofday() from host.
See usage example in open-vm-tools TimeSyncReadHost() function.

Reviewed-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
---
 hw/i386/vmport.c         | 21 +++++++++++++++++++++
 include/hw/i386/vmport.h |  1 +
 2 files changed, 22 insertions(+)

diff --git a/hw/i386/vmport.c b/hw/i386/vmport.c
index ef94f4fe78c6..15632c579199 100644
--- a/hw/i386/vmport.c
+++ b/hw/i386/vmport.c
@@ -55,6 +55,7 @@ typedef struct VMPortState {
 
     uint32_t vmx_version;
     uint8_t vmx_type;
+    uint32_t max_time_lag_us;
 
     uint8_t version;
 } VMPortState;
@@ -157,6 +158,20 @@ static uint32_t vmport_cmd_ram_size(void *opaque, uint32_t addr)
     return ram_size;
 }
 
+static uint32_t vmport_cmd_time(void *opaque, uint32_t addr)
+{
+    X86CPU *cpu = X86_CPU(current_cpu);
+    qemu_timeval tv;
+
+    if (qemu_gettimeofday(&tv) < 0) {
+        return UINT32_MAX;
+    }
+
+    cpu->env.regs[R_EBX] = (uint32_t)tv.tv_usec;
+    cpu->env.regs[R_ECX] = port_state->max_time_lag_us;
+    return (uint32_t)tv.tv_sec;
+}
+
 /* vmmouse helpers */
 void vmmouse_get_data(uint32_t *data)
 {
@@ -203,6 +218,7 @@ static void vmport_realizefn(DeviceState *dev, Error **errp)
     vmport_register(VMPORT_CMD_GETRAMSIZE, vmport_cmd_ram_size, NULL);
     if (s->version > 1) {
         vmport_register(VMPORT_CMD_GETBIOSUUID, vmport_cmd_get_bios_uuid, NULL);
+        vmport_register(VMPORT_CMD_GETTIME, vmport_cmd_time, NULL);
     }
 }
 
@@ -218,6 +234,11 @@ static Property vmport_properties[] = {
     DEFINE_PROP_UINT32("vmx-version", VMPortState, vmx_version, 6),
     DEFINE_PROP_UINT8("vmx-type", VMPortState, vmx_type,
                       VMX_TYPE_SCALABLE_SERVER),
+    /*
+     * Max amount of time lag that can go uncorrected.
+     * Value taken from VMware Workstation 5.5.
+     **/
+    DEFINE_PROP_UINT32("max-time-lag", VMPortState, max_time_lag_us, 1000000),
 
     DEFINE_PROP_END_OF_LIST(),
 };
diff --git a/include/hw/i386/vmport.h b/include/hw/i386/vmport.h
index 7f33512ca6f0..50416c8c8f3e 100644
--- a/include/hw/i386/vmport.h
+++ b/include/hw/i386/vmport.h
@@ -8,6 +8,7 @@ typedef enum {
     VMPORT_CMD_GETVERSION       = 10,
     VMPORT_CMD_GETBIOSUUID      = 19,
     VMPORT_CMD_GETRAMSIZE       = 20,
+    VMPORT_CMD_GETTIME          = 23,
     VMPORT_CMD_VMMOUSE_DATA     = 39,
     VMPORT_CMD_VMMOUSE_STATUS   = 40,
     VMPORT_CMD_VMMOUSE_COMMAND  = 41,
-- 
2.20.1